This proposal is a competitive renewal which examines the long-term (5 years) follow-up effects of a six-month exercise program (Illinois Active Aging) on psychological function in older adults (N=174). In addition, a media and telephone booster intervention to increase physical activity and, in turn, psychological function in the original participant sample is proposed. The specific aims are: (a) To examine the shape and form of physical activity participation, physical fitness, and psychosocial function at approximately five years beyond entry into a six-month walking or stretching/toning exercise intervention; (b) To determine which social, psychological, behavioral, and physical factors determine long- term physical activity maintenance; (c) To examine the effects of a six-month telephone and mail-based intervention on physical activity participation and psychological function five years beyond the initial intervention. It is expected that the "booster" intervention, as compared to the control group will increase their levels of physical activity thereby increasing their physical fitness levels. In addition, it is expected that the intervention will lead to enhanced self-efficacy, self- esteem, and subjective well-being; (d) Finally, the role played by physical activity participation, fitness, and self-efficacy in improved psychological function will be examined. There are several strengths associated with the proposed studies. First, little is known about the long-term effects of exercise programs on the physical and psychological health of older adults beyond the more immediate effects of activity interventions. This project proposes to employ multiple sample latent growth curve methods to map the growth and form of change in these health parameters five years beyond the start of the original randomized controlled trial. No exercise trials to date have attempted to follow subjects for such a length of time. Second, we the proposal is theoretically grounded rather than descriptive and we expect changes in self-efficacy to be instrumental in changes in function. Third, we propose to implement a media/telephone intervention to try to reverse the expected declines in physical activity and psychosocial function. Typically, after standard follow-up assessments in exercise trials, no such efforts are made. As such, the proposed study represents a unique attempt to further understand the role played by physical activity in the psychological health of older Americans.